How visual is the “groupitizing”? The impact of visual deprivation over its emergence

Sensitive Period for a Multimodal Response in Human Visual Motion Area MT/MST

The ability to identify images is necessary to function well in a modern society. People who are visually impaired (that is, those who are blind or have low vision) need to understand graphics on a level that is far beyond what is currently taught in school curricula (Aldrich & Sheppard, 2001). Even adequately designed tactile graphics have to be taught systematically for individuals who are visually impaired to understand them (Cryer & Gunn, 2008). Kennedy (1984, 1993, 2003) pointed out that even though people who are blind do not have visual experiences, they can use their tactile sense as a substitute to learn spatial representation; moreover, their spatial representation strategies are often no different from those of individuals with no visual impairment; they can even draw from a linear perspective. However, the kind of training in drawing given to the participants in Kennedy's research was not specified. D'Angiulli (2007) reported certain commonalities and overlapping concepts in the drawing principles of people who are blind and sighted. People who are blind have no problem with simple two-dimensional shapes in terms of both tactile and cognitive abilities. However, some scholars have reported that people without visual experience, such as those with congenital blindness, are incapable of drawing graphics that involve perspective without prior education; they have also suggested that visual experience is a prerequisite to certain types of drawing (I & Shiu, 2001, 2010). In particular, they found that even at age 20, people who are totally blind and have never had visual and drawing experiences were only able to draw a square when asked to draw a cube. Therefore, whether an individual without visual experience has the ability to draw from a linear perspective is questionable, and education has been recognized as the key factor. In Taiwan, education for people who are blind is traditionally focused on vocational training. The majority of people who are blind work in the massage industry, and few of them have had the opportunity to explore and participate in arts activities. How well a person who is blind can draw is directly related to his or her education, environment, social development policies, and level of familiarity in identifying objects (I & Shiu, 2010). The earlier a person who is blind undergoes education in graphic drawing, the better his or her performance will be (I & Shiu, 2010). The three cases studied by Kennedy (2003) and by Kennedy and Juricevic (2003, 2006) also illustrated the importance of early education in graphic expression as well as of cultivating an interest in learning. Even with respect to encoding information from tactile maps, Ungar, Blades, and Spencer (1995) considered education to be an instrument that can shorten the gap between people who are blind and sighted people. People who are blind often draw common objects used in daily living skills, such as cups and plates, in a way that is similar to how sighted persons do, but difficulties emerge when they try to present the depth of an object through projection lines (I & Shiu, 2001, 2008, 2010). A cube is more difficult to draw than a cup (Cox, 1986) because a cube involves complex projection lines. Sighted people have to draw objects that they see in three dimensions on a two-dimensional plane. The research reported here explored whether people who are blind without any visual experience are able to learn how to draw perspective through education. The researcher (the first author) used a cube as the stimulus, together with special teaching aids, to help a participant with congenital total blindness understand the drawing method used by his sighted counterparts. The study also aimed to observe how instructional assistance can enhance the drawing capability of an adult with congenital total blindness. METHOD Participant Han, aged 25, is congenitally and totally blind with no previous experience in drawing. …

Introduction Delays in theory of mind (ToM) of children who are congenitally blind have often been attributed to the absence of visual and social experiences. However, these delays could also be partly due to neural factors. In some children, the blindness itself has neural causes (ocular-plus blindness). Children whose blindness has an ocular-plus cause may be more delayed in ToM than children with blindness due to ocular causes. Methods In the current study, performances of children with congenital ocular-plus blindness ( n = 22) and congenital ocular blindness ( n = 9) were compared with sighted children ( n = 103) on ToM tasks designed for children with blindness. Results Compared with sighted children, ToM performance was delayed in children with ocular-plus blindness, but not in children with ocular blindness. Discussion ToM development in children with congenital blindness could be related to factors other than the loss of a sensory function and the lack of visual social and communicative experiences. Implications for practitioners The specific ToM deficits in children with ocular-plus blindness may help in developing new research paradigms that consider delays in ToM in children with congenital blindness.

Dual coding of knowledge in the human brain.

It is generally acknowledged that congenitally blind individuals develop superior sensory abilities in order to compensate for their lack of vision. Substantial research has been done on somatosensory and auditory sensory information processing of the blind. However, relatively little information is available about compensatory plasticity in the olfactory domain. Although previous studies indicate that blind individuals have superior olfactory abilities, no studies so far have investigated their sense of smell in relation to social and affective communication. The current study compares congenitally blind and normal sighted individuals in their ability to discriminate and identify emotions from body odours. A group of 14 congenitally blind and 14 age- and sex-matched sighted control subjects participated in the study. We compared participants' abilities to detect and identify by smelling sweat from donors who had been watching excerpts from emotional movies showing amusement, fear, disgust, or sexual arousal. Our results show that congenitally blind subjects outperformed sighted controls in identifying fear from male donors. In addition, there was a strong tendency that blind individuals were also better in detecting disgust. Our findings reveal that congenitally blind individuals are better at identifying ecologically important emotions and provide new insights into the mechanisms of social and affective communication in blindness.

Visual deprivation leads to behavioural adaptations. Early visual deprivation has greater effects on sensory systems compared with late visual deprivation. Although this has been well studied, the impact of visual deprivation on pain sensitivity has scarcely been investigated. In humans, one study indicates that pain sensitivity is increased in early, but not late-onset blindness. In animals, one study indicates that sensitivity to noxious stimulation is increased in anophthalmic mice, but the impact of late visual deprivation on sensitivity remains unknown. The aim of this behavioural study was to examine sensitivity to noxious stimulation in mice with early and late visual deprivation. We hypothesized that visual deprivation would have different effects on sensitivity to noxious stimulation depending on its onset. In Experiment 1, mechanical and thermal sensitivity was examined in four ZRDBA mouse groups: sighted mice, anophthalmic mice, dark-reared sighted mice and adult sighted mice deprived of vision for one week. In Experiment 2, mechanical and thermal sensitivity was examined in adult sighted ZRDBA mice deprived of vision for two months. Anophthalmic and dark-reared mice showed mechanical and thermal hypersensitivity, while the one-week visual deprivation did not alter sensitivity. The two-month deprivation also resulted in mechanical and thermal hypersensitivity. These results indicate that early visual deprivation, regardless of the integrity of the visual system, induces hypersensitivity. Moreover, the present findings indicate that late visual deprivation may induce mechanical and thermal hypersensitivity, although this depends on visual deprivation duration. These results have implications for the biological significance of pain in the blind. Sensory deprivation induces behavioural adaptions. For most sensory systems, the extent of these adaptations generally depends on the stage of cerebral development. In contrast, the present results indicate that for the nociceptive system, both early and late visual deprivation have similar effects. Anophthalmic, dark-reared mice and adult mice deprived of vision for two months showed thermal and mechanical hypersensitivity. This shows a clear interaction between visual and nociceptive systems and has implications for the biological significance of pain in the blind.

We have recently shown that visual deprivation from birth exacerbates responses to painful thermal stimuli. However, the mechanisms underlying pain hypersensitivity in congenital blindness are unclear. To study the contribution of Aδ- and C-fibres in pain perception, we measured thresholds and response times to selective C- and Aδ-fibre activation in congenitally blind, late blind and normally sighted participants. Ultrafast constant-temperature heat pulses were delivered to the hand with a CO2 laser using an interleaved adaptive double staircase procedure. Participants were instructed to respond asquickly as possible when detecting a laser-induced sensation. We useda650ms cut-off criterion to distinguish fast Aδ- from slow C-fibre-mediated sensations. Congenitally blind participants showed significantly faster reaction times to C- but not to Aδ-fibre-mediated sensations. In contrast, thresholds for Aδ- and C-fibre stimulation did not differ between groups. Late blind individuals did not differ from sighted controls in any aspect. A follow-up experiment using only suprathreshold stimuli for Aδ- and C-fibre activation confirmed these findings and further showed that congenitally blind individuals detected significantly more C-fibre-mediated stimuli than sighted controls. A decomposition analysis of the reaction times indicated that the faster response times in the congenitally blind are due to more efficient central processing of C-fibre-mediated sensations. The increased sensitivity to painful thermal stimulation in congenital blindness may be due to more efficient central processing of C-fibre-mediated input, which may help to avoid impending dangerous encounters with stimuli that threaten the bodily integrity. WHAT DOES THIS STUDY ADD?: Hypersensitivity to heat pain in congenital blindness is associated with faster responses to C-fibre activation, likely caused by more efficient central processing of C-fibre-mediated input.

Organization and Reorganization of Sensory-Deprived Cortex

Event Abstract Back to Event White matter tract of orthographic recognition and its functional plasticity: Evidence from patients and congenital blinds Ke Wang1, Xiaonan Li1, Ruiwang Huang2, Junhua Ding1, Luping Song3 and Zaizhu Han1* 1 Beijing Normal University, State Key Laboratory of Cognitive Neuroscience and Learning, China 2 South China Normal University, School of Psychology, China 3 Beijing Rehabilitation Hospital, Capital Medical University, College and China Rehabilitation Research Center, China Orthographic recognition, a pivotal stage during word reading, has been found to be supported by a neuroanatomical network. However, the white-matter connectivity in this network remains unclear because prior findings might be confounded by impure behavioral measures, potential brain structural reorganization, or limited samples of subjects and white-matter tracts. It is also unclear which part of the connectivity is inherent and which part is determined by postnatal visual experience. To address these issues, we separately investigated the relationship between the integrity of 20 major tracts in the whole brain and the pure orthographic index across 70 patients with short-term brain damage and across 31 congenitally blind readers. The integrity of the tracts was evaluated using the mean fractional anisotropy value (for patients and blind readers) and the lesion volume percentage (for patients). The orthographic index was measured by the residual of accuracies in the orthographic tasks, regressing out accuracies in the corresponding non-orthographic tasks. The observed effects of orthographic tracts were further validated by ruling out the influence of numerous potential confounding variables. We found that the left inferior longitudinal fasciculus (ILF) was the only orthographic tract whose integrity values were significantly correlated with orthographic scores in the patients. Moreover, when the tract was split into the anterior and posterior branches along the visual word fusiform area (VWFA), both branches contributed to orthographic recognition in the patients. More importantly, the visual deprivation forced only the posterior but not the anterior branch of the tract to engage in orthographic processing, since the integrity values of the posterior rather than the anterior branch were significantly correlated with the performance of orthographic recognition in the congenitally blind subjects. Furthermore, the observed effects could not be accounted for by the potential confounding factors. These findings strengthen the vital role of the left ILF in orthographic processing and reveal the functional neuroplasticity of this tract in response to visual experience deprivation. Figure 1 Keywords: Orthographic recognition, white-matter tract, lesion-behavior mapping, Brain-damage patients, Congenital blindness Conference: Academy of Aphasia 56th Annual Meeting, Montreal, Canada, 21 Oct - 23 Oct, 2018. Presentation Type: poster presentation Topic: Eligible for a student award Citation: Wang K, Li X, Huang R, Ding J, Song L and Han Z (2019). White matter tract of orthographic recognition and its functional plasticity: Evidence from patients and congenital blinds. Conference Abstract: Academy of Aphasia 56th Annual Meeting. doi: 10.3389/conf.fnhum.2018.228.00055 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Apr 2018; Published Online: 22 Jan 2019. * Correspondence: Prof. Zaizhu Han, Beijing Normal University, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing, China, zzhhan@bnu.edu.cn Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ke Wang Xiaonan Li Ruiwang Huang Junhua Ding Luping Song Zaizhu Han Google Ke Wang Xiaonan Li Ruiwang Huang Junhua Ding Luping Song Zaizhu Han Google Scholar Ke Wang Xiaonan Li Ruiwang Huang Junhua Ding Luping Song Zaizhu Han PubMed Ke Wang Xiaonan Li Ruiwang Huang Junhua Ding Luping Song Zaizhu Han Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The Bouba-Kiki effect is the systematic mapping between round/spiky shapes and speech sounds (“Bouba”/“Kiki”). In the size-weight illusion, participants judge the smaller of two equally-weighted objects as being heavier. Here we investigated the contribution of visual experience to the development of these phenomena. We compared three groups: early blind individuals (no visual experience), individuals treated for congenital cataracts years after birth (late visual experience), and typically sighted controls (visual experience from birth). We found that, in cataract-treated participants (tested visually/visuo-haptically), both phenomena are absent shortly after sight onset, just like in blind individuals (tested haptically). However, they emerge within months following surgery, becoming statistically indistinguishable from the sighted controls. This suggests a pivotal role of visual experience and refutes the existence of an early sensitive period: A short period of experience, even when gained only years after birth, is sufficient for participants to visually pick-up regularities in the environment, contributing to the development of these phenomena.

Background: Visual input is thought to influence spatial cognition and language. While blind individuals often rely on egocentric spatial representations, it remains unclear whether and how visual deprivation affects dream-related language. This study applied speech graph analysis (SGA) to investigate linguistic differences in dream reports from congenitally blind (CB), late blind (LB), and sighted control (SC) individuals. Methods: We retrospectively analyzed 333 dream reports from an open-access database (DreamBank): 118 from CB, 75 from LB, and 140 from SC individuals. Graph-theoretical metrics of structural and semantic speech organization were extracted using validated NLP and SGA pipelines, including recurrence (L2/L3), connectivity (LSC), and lexical diversity (nodes). Results: Compared to SC, both CB and LB groups showed significantly reduced lexical diversity and increased long-range recurrence (LSC), suggesting greater linguistic cohesiveness. LB reports showed a specific increase in short-range recurrence cycles (L2, L3), not observed in CB. Spectral analysis supported these group differences, indicating altered graph-wide connectivity properties in blind groups. Conclusions: Blind individuals demonstrate distinct structural and semantic features in dream-related language, consistent with more egocentric narrative construction. These findings support a potential role of sensory experience in shaping cognitive-linguistic encoding. Further prospective studies are needed to explore underlying neural mechanisms and developmental trajectories.

How does the Visual Cortex of the Blind Acquire Auditory Responsiveness?

As neuroscience and rehabilitative techniques advance, age-old questions concerning the visual experience of those who gain sight after blindness, once thought to be philosophical alone, take center stage and become the target for scientific inquiries. In this study, we employ a battery of visual perception tasks to study the unique experience of a small group of children who have undergone vision-restoring cataract removal surgery as part of the Himalayan Cataract Project. We tested their abilities to perceive in three dimensions (3D) using a binocular rivalry task and the Brock string task, perceive visual illusions, use cross-modal mappings between touch and vision, and spatially group based on geometric cues. Some of the children in this study gained a sense of sight for the first time in their lives, having been born with bilateral congenital cataracts, while others suffered late-onset blindness in one eye alone. This study simultaneously supports yet raises further questions concerning Hubel and Wiesel's critical periods theory and provides additional insight into Molyneux's problem, the ability to correlate vision with touch quickly. We suggest that our findings present a relatively unexplored intermediate stage of 3D vision development. Importantly, we spotlight some essential geometrical perception visual abilities that strengthen the idea that spontaneous geometry intuitions arise independently from visual experience (and education), thus replicating and extending previous studies. We incorporate a new model, not previously explored, of testing children with congenital cataract removal surgeries who perform the task via vision. In contrast, previous work has explored these abilities in the congenitally blind via touch. Taken together, our findings provide insight into the development of what is commonly known as the visual system in the visually deprived and highlight the need to further empirically explore an amodal, task-based interpretation of specializations in the development and structure of the brain. Moreover, we propose a novel objective method, based on a simple binocular rivalry task and the Brock string task, for determining congenital (early) vs. late blindness where medical history and records are partial or lacking (e.g., as is often the case in cataract removal cases).

The superiority in voice processing of the blind arises from neural plasticity at sensory processing stages

Effects of congenital blindness on the subcortical representation of speech cues